关键词: 双季稻, 减量施肥, 生物炭, 腐植酸, 产量, 养分流失

Abstract: Field experiment was conducted to study the effects of each 20% reduction of nitrogen and phosphorus and application of humic acid(900 kg/ha) and biochar(2 250 kg/ha) on rice yield and loss of nitrogen and phosphorus,so as to screen out the fertilization technology which could reduce the pollution of non-point source in paddy field.The results showed that compared with conventional fertilization,20% reduction of nitrogen and phosphorus,and application of biochar and humic acid after 20% reduction of nitrogen and phosphorus,had no significant effect on rice yield and the contents of nitrogen,phosphorus and potassium in straw and grain.However,compared with the treatment with 20% reduction of nitrogen and phosphate,application of biochar and humic acid on the basis of 20% reduction of nitrogen and phosphate fertilizer could significantly increase the plant height,filled grain number per panicle,seed setting rate and yield of double-cropping rice.The concentrations of nitrogen and phosphorus in field surface water of conventional fertilization treatment were significantly higher than those of other treatments with 20% reduction of nitrogen and phosphorus and application of biochar and humic acid.In addition,compared with the treatment with 20% reduction of nitrogen and phosphorus,the average total nitrogen and phosphorus concentrations of the treatments with biochar and humic acid based on 20% reduction of nitrogen and phosphorus reduced by 3.18%—16.35% and 3.23%—13.21% respectively,which significantly reduced the risk of nitrogen and phosphorus loss. Among them,the treatment with biochar and humic acid based on 20% reduction of nitrogen and phosphorus was the best fertilization method with high yield and less loss of nitrogen and phosphorus. Under this way of fertilization,compared with the treatment with 20% reduction of nitrogen and phosphate,the concentrations of total nitrogen,soluble nitrogen,ammonium nitrogen,nitrate nitrogen,total phosphorus and soluble phosphorus in the field surface water of early rice decreased by 16.35%,13.45%,17.39%,14.06%,13.21% and 13.95%,and by 10.51%,10.78%,9.43%,16.90%,12.90% and 13.33% in the field surface water of late rice.

Key words: ouble-cropping rice, Reducing application rate of fertilizer, Biochar, Humic acid, Yield, Nutrient loss